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        <div>
            <div><h3 class="title">
                <a name="asio.reference.buffer_copy"></a><a class="link" href="buffer_copy.html" title="buffer_copy">buffer_copy</a>
            </h3></div>
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    <p>
        <a class="indexterm" name="asio.indexterm.buffer_copy"></a>
    </p>
    <p>
        The <code class="computeroutput"><span class="identifier">asio</span><span class="special">::</span><span
            class="identifier">buffer_copy</span></code> function is used to copy bytes
        from a source buffer (or buffer sequence) to a target buffer (or buffer sequence).
    </p>
    <p>
        Copies bytes from a source buffer sequence to a target buffer sequence.
    </p>
    <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
    <span class="keyword">typename</span> <a class="link" href="MutableBufferSequence.html"
                                             title="Mutable buffer sequence requirements">MutableBufferSequence</a><span
                class="special">,</span>
    <span class="keyword">typename</span> <a class="link" href="ConstBufferSequence.html"
                                             title="Constant buffer sequence requirements">ConstBufferSequence</a><span
                class="special">&gt;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <a class="link"
                                                                                                            href="buffer_copy/overload1.html"
                                                                                                            title="buffer_copy (1 of 2 overloads)">buffer_copy</a><span
                class="special">(</span>
    <span class="keyword">const</span> <span class="identifier">MutableBufferSequence</span> <span
                class="special">&amp;</span> <span class="identifier">target</span><span class="special">,</span>
    <span class="keyword">const</span> <span class="identifier">ConstBufferSequence</span> <span
                class="special">&amp;</span> <span class="identifier">source</span><span class="special">);</span>
  <span class="emphasis"><em>» <a class="link" href="buffer_copy/overload1.html" title="buffer_copy (1 of 2 overloads)">more...</a></em></span>
</pre>
    <p>
        Copies a limited number of bytes from a source buffer sequence to a target
        buffer sequence.
    </p>
    <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
    <span class="keyword">typename</span> <a class="link" href="MutableBufferSequence.html"
                                             title="Mutable buffer sequence requirements">MutableBufferSequence</a><span
                class="special">,</span>
    <span class="keyword">typename</span> <a class="link" href="ConstBufferSequence.html"
                                             title="Constant buffer sequence requirements">ConstBufferSequence</a><span
                class="special">&gt;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <a class="link"
                                                                                                            href="buffer_copy/overload2.html"
                                                                                                            title="buffer_copy (2 of 2 overloads)">buffer_copy</a><span
                class="special">(</span>
    <span class="keyword">const</span> <span class="identifier">MutableBufferSequence</span> <span
                class="special">&amp;</span> <span class="identifier">target</span><span class="special">,</span>
    <span class="keyword">const</span> <span class="identifier">ConstBufferSequence</span> <span
                class="special">&amp;</span> <span class="identifier">source</span><span class="special">,</span>
    <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span
                class="identifier">max_bytes_to_copy</span><span class="special">);</span>
  <span class="emphasis"><em>» <a class="link" href="buffer_copy/overload2.html" title="buffer_copy (2 of 2 overloads)">more...</a></em></span>
</pre>
    <p>
        The <code class="computeroutput"><span class="identifier">buffer_copy</span></code> function
        is available in two forms:
    </p>
    <div class="itemizedlist">
        <ul class="itemizedlist" type="disc">
            <li class="listitem">
                A 2-argument form: <code class="computeroutput"><span class="identifier">buffer_copy</span><span
                    class="special">(</span><span class="identifier">target</span><span class="special">,</span> <span
                    class="identifier">source</span><span class="special">)</span></code>
            </li>
            <li class="listitem">
                A 3-argument form: <code class="computeroutput"><span class="identifier">buffer_copy</span><span
                    class="special">(</span><span class="identifier">target</span><span class="special">,</span> <span
                    class="identifier">source</span><span class="special">,</span> <span class="identifier">max_bytes_to_copy</span><span
                    class="special">)</span></code>
            </li>
        </ul>
    </div>
    <p>
        Both forms return the number of bytes actually copied. The number of bytes
        copied is the lesser of:
    </p>
    <div class="itemizedlist">
        <ul class="itemizedlist" type="disc">
            <li class="listitem">
                <code class="computeroutput"><span class="identifier">buffer_size</span><span
                        class="special">(</span><span class="identifier">target</span><span
                        class="special">)</span></code>
            </li>
            <li class="listitem">
                <code class="computeroutput"><span class="identifier">buffer_size</span><span
                        class="special">(</span><span class="identifier">source</span><span
                        class="special">)</span></code>
            </li>
            <li class="listitem">
                <code class="computeroutput"><span class="identifier">If</span></code> specified, <code
                    class="computeroutput"><span class="identifier">max_bytes_to_copy</span></code>.
            </li>
        </ul>
    </div>
    <p>
        This prevents buffer overflow, regardless of the buffer sizes used in the
        copy operation.
    </p>
    <p>
        Note that <a class="link" href="buffer_copy.html" title="buffer_copy"><code class="computeroutput"><span
            class="identifier">buffer_copy</span></code></a>
        is implemented in terms of <code class="computeroutput"><span class="identifier">memcpy</span></code>,
        and consequently it cannot be used to copy between overlapping memory regions.
    </p>
    <h5>
        <a name="asio.reference.buffer_copy.h0"></a>
        <span><a name="asio.reference.buffer_copy.requirements"></a></span><a class="link"
                                                                              href="buffer_copy.html#asio.reference.buffer_copy.requirements">Requirements</a>
    </h5>
    <p>
        <span class="emphasis"><em>Header: </em></span><code class="literal">asio/buffer.hpp</code>
    </p>
    <p>
        <span class="emphasis"><em>Convenience header: </em></span><code class="literal">asio.hpp</code>
    </p>
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